1. Filed of the Invention
The present invention relates to a wheel bearing device (hub bearing) used in automobiles, etc., particularly to a wheel bearing device having unitarily built therein a wheel speed detection means for an ABS (antilock brake system).
2. Prior Art
A wheel bearing device, as shown in FIG. 6, comprises a hub ring 1, an inner ring 2, a double row of rolling bodies 3, and an outer ring 4. The outer peripheral surface of the hub ring 1 is formed with a wheel attaching flange 1a for fixing a wheel at the outboard end, and a first raceway surface 5a in the intermediate region. The inboard end of the hub ring 1 is formed with a small-diametered stepped portion 1b having a reduced outer diameter, and the inner ring 2 formed with a second raceway surface 5b on its outer peripheral surface is fitted on the small-diametered stepped portion 1b. The inner peripheral surface of an outer ring 4 is formed with a double row of raceway surfaces 6 opposed to the first and second raceway surfaces 5a and 5b, and a double row of rolling bodies 3 are installed between the first and second raceway surfaces 5a, 5b and the double row of raceway surfaces 6. The outer ring 4 is fixed to an unillustrated suspension device through a flange 4a formed on the outer peripheral surface.
As for a design in which a wheel speed detecting means for ABS is built in this wheel bearing device, there is known an arrangement wherein, as shown in the same figure, a pulser ring 7 serving as a pulse generator is installed between the first and second raceway surfaces 5a and 5b on the outer peripheral surface of the hub ring 1 and a sensor 8 serving as a pulse detector extends through the outer ring 4 to be opposed to the pulser ring 7.
When the assembly of the wheel bearing device is to be assembled in a car body, normally, of the outer peripheral surface of the outer ring 4, the inboard side of the flange 4a is inserted in the inner peripheral surface of an attaching member (knuckle) extending from a suspension device. However, in the case where the flange 4a is deviated to the outboard side of the outer ring 4, as shown, the outer peripheral surface of the outer ring is covered by the knuckle in many axial regions, so that as it stands the ABS sensor 8 interferes with the knuckle, making the insertion impossible. Therefore, the attached position of the ABS sensor 8 has to be reconsidered, but it is not easy to secure a space for attachment, particularly it is considerably difficult to arrange the sensor 8 in the bearing inner space (the space between the double row of rolling bodies
Accordingly, an object of the invention is to provide a wheel bearing device that makes it possible to install an ABS sensor even if the flange of the outer ring is deviated to the outboard side
A wheel bearing device according to an embodiment of the invention comprises a rotor having a double row of raceway surfaces and adapted to have a wheel fixed thereto, a stator having a double row of raceway surfaces and a flange for fixing to an attaching member on the car body side, and a double row of rolling bodies interposed between the respective raceway surfaces of the rotor and stator, the wheel being rotatably supported on the car body, wherein installed between said double row of raceway surfaces of the rotor is a sensed part, and a sensor opposed to said sensed part is held by a holding member held between said flange of the stator and said attaching member.
According to the invention, even when the flange of the stator is deviated to the outboard side, a wheel rpm detection means can be added to the wheel bearing device; particularly, it can be easily disposed in the bearing inner space, which is advantageous for the operating stability of the sensor. Further, the wheel bearing device may be unitized (modularized) in a form that includes the attaching members on the car body side and the operability in assembling the wheel bearing device in the car body is improved. Specifically, since the holding member is thus interposed between the flange of the stator and the attaching member, such as a knuckle, to hold the sensor, then the sensor can be easily disposed in the bearing inner space even if the flange of the stator is in a position deviated to the outboard side. Since the bearing inner space is a sealed space whose opposite ends are sealed, the sensed part and the sensor can be protected from dust, salt water, stones, etc., and stabilized detection of speed becomes possible. Further, the wheel bearing device can be unitized in a form that includes the attaching member, and the operability in assembling the wheel bearing device and attaching it to the car body is improved.
The rotor may include, for example, a hub ring and an inner ring fitted in the hub ring. In this case, one of the double row of raceway surfaces of the rotor may be formed in the hub ring and the other in the inner ring.
Further, the rotor may include a hub ring and the outer joint member of a constant velocity joint connected to the hub ring. This arrangement is suitable as a wheel bearing device for driving wheels. In this case, one of the double row of raceway surfaces of the rotor may be formed in the hub ring and the other in the outer joint member of the constant velocity joint.
The hub ring and the outer joint member may be fitted together and crimped by at least locally expanding or contracting the diameter of the fitting portions, thereby preventing them from loosening so that they can be reliably joined together.
The flange of the stator, holding member, and the attaching member disposed on the car body side are joined together as by bolts. In this case, if the holding member is made of resin and the periphery of the bolt hole is made of metal, then weight reduction can be attained and even when the knuckle is made of aluminum alloy, the presence of the resin in the interface between the steel and the aluminum prevents the steel members (the stator, etc.) from rusting due to the difference in ionization tendency.
The present invention has for its another object the provision of a wheel bearing device that dispenses with the bolting of the outer ring to the knuckle, reduces the number of parts, the number of man-hours of assembly, and the number of man-hours needed to process the outer ring, and readily realizes light weight and size compaction.
A wheel bearing device according to another embodiment of the invention comprises a fixed member attached to a car body, an outer member fitted in the fixed member and formed with a double row of raceway surfaces on its inner periphery, an inner member formed with a double row of raceway surfaces on its outer peripheral surface opposed to the raceway surfaces of the outer member and having a wheel attaching flange, a double row of rolling bodies interposed between the raceway surfaces of the outer and inner members, the wheel being rotatably supported by the car body, the wheel bearing device being characterized in that an speed detecting sensor is fitted in a hole formed to extend radially through the fixed and outer members and is opposed to a sensed part disposed between the raceway surfaces of the inner member.
In the wheel bearing device, the speed detecting sensor is fitted in the hole formed to extend radially through the fixed and outer members and is opposed to a sensed part disposed between the raceway surfaces of the inner member; this eliminates the need for forming a car body attaching flange on the outer periphery of the outer member and bolting it to the knuckle, making it possible to realize light weight and cost reduction by an amount corresponding to at least the bolts, making it easier to attain light weight and cost reduction since there is no need to form the flange, allowing unitization (modularization), cutting down on the operation of attachment to the car body. Thus, it is possible to reduce the number of parts, the number of man-hours of assembly, the number of man-hours needed to process the outer ring of the bearing, and to realize light weight and size compaction for the entire device, the practical value of the invention being high.
The sensor may be fitted in the hole in the fixed and outer members through a cylindrical member, so that the strength of the sensor itself can be improved and even if there is no allowance for tightening the outer member fitted in the fixed member, creeping of the outer member can be prevented by the sensor.
A construction in which a pin-like member is fitted in a hole formed to extend radially through the fixed and outer members or a construction in which a pin-like member is fitted in a hole formed to extend radially through the fixed member and is engaged in an annular groove formed in the outer surface of the outer member, may be employed, then the outer member can be axially positioned and fixed, it being also possible to prevent the outer member from creeping.
The pin-like member may be fitted in the hole in the fixed member through an elastic member so that the pin-like member can be projected and retracted and it can be engaged in the annular groove of the outer member by a predetermined urging force. In this case, the pin-like member can be fitted in the fixed member in advance by deformation of the elastic member, improving the assembling operation and, if the sensor is removed, the outer member can be withdrawn with a predetermined axial load applied thereto.
The inner surface of the fixed member and the outer surface of the outer member may be formed with an annular groove and a locking member is installed that bites into the annular grooves, so that the outer member can be axially positioned and fixed. In addition, the locking member may preferably be in the form of a diametrically contractible end-having snap ring having elastic recovery force. The snap ring may be made circumferentially uneven, so that the outer member can be prevented from axial playing.
An alternative arrangement for axially positioning the outer member may be such that the inner surface of the fixed member and the outer surface of the outer member are each formed with an annular groove, a tangential hole communicating with the annular grooves is formed in the fixed member, and a locking member is installed that is inserted from the tangential hole and bites into the annular grooves. In addition, the locking member may preferably be a wire or bearing steel ball inserted from the tangential hole communicating with the annular groove of the fixed member.
The present invention has for its other object to simplify the attaching operation of such wheel bearing device, to reduce the number of parts and the number of man-hours of assembly, to increase the operating stability of the wheel speed detecting means, etc.
A wheel bearing device according to other embodiment of the invention comprises rotary raceway surfaces formed in a double row in a rotor rotating together with a wheel, fixed raceway surfaces formed in a double row on the car body side, a double row of rolling bodies interposed between the rotary raceway surfaces and the fixed raceway surfaces, the wheel being supported for rotation with respect to an attaching member extending from the car body, wherein the inner peripheral surface of said attaching member is provided with an opposing portion disposed between the double row of rotary raceway surfaces and opposed to the outer peripheral surface of the rotor, and a pair of outer rings having the fixed raceway surfaces are fitted in the inner peripheral surface of the attaching member and on the axial opposite sides of the opposing portion.
Fitting a pair of outer rings having fixed raceway surfaces in the inner peripheral surface of the attaching member in this manner makes it possible to attach the fixed side of the wheel bearing device to the attaching member on the car body side without using fixing means such as bolts, to reduce the number of parts and the number of man-hours of assembly by an amount corresponding to the fixing means, whereby low cost and light weight can be achieved. Further, the wheel bearing device may be unitized (modularized) in a form that includes the attaching member, so that the operability in attaching the wheel bearing device to the car body is improved. Since the opposing portion opposed to the outer peripheral surface of the rotor between the rotary raceway surfaces is interposed between the two outer rings, an auxiliary part that should, as a precondition, be in opposed relation to the rotor, for example, a sensor for detecting the speed of the rotor can be disposed.
In the above arrangement, either the outer rings may be integrated with the attaching member (integral formation) or both of them may be integrated with the attaching member (integral formation). The integrating methods include among others casting and insert-molding, and further reduction of the number of parts and the number of man-hours of assembly can be achieved by these techniques.
If the opposing portion is formed as a flange projecting radially inward and the end surfaces of the outer rings are engaged with this flange, it becomes possible to axially position the outer rings and to support the axial preload on the bearing device.
The sensor can be disposed on the opposing portion as described above. In this case, since the sensor comes to be disposed in the bearing inner space having its axial opposite ends sealed by the seals, the sensor can be protected from dust, salt water, stones, etc., so that stabilized signal detection becomes possible. The seals in this case can be used also as seals for the bearing device, eliminating the need for using exclusive seals for the sensor, so that reduction of the number of parts and the number of man-hours of assembly, improvement in space efficiency, etc. are attained. The sensor can be attached so that it extends through the attaching member, and the number of man-hours of processing can be reduced since the conventional attaching holes for the outer ring become unnecessary. Further, positioning of the attaching holes between the outer rings and the attaching member is not necessary, so that the assembling operation is improved.
The sensed part is disposed on the outer peripheral surface of the rotor opposed to the sensor. If this sensed part is in the form of something that produces pulses in proportion to speed, for example, a pulse generator having a circumferentially disposed projection of magnetic material, the speed of the rotor can be accurately detected. The detected data can be utilized, for example, as rpm data for ABS""s.
The rotor is, for example, one having a hub ring and an inner ring fitted in the hub ring. In this case, of the double row of rotary raceway surfaces formed in the rotor, one row may be formed in the hub ring and the other in the inner ring.
The rotor may be one having a hub ring and the outer joint member of a constant velocity joint joined to the hub ring. This is preferable as a wheel bearing device for driving wheels. In this case, of the double row of rotary raceway surfaces provided in the rotor, one row of raceway surfaces may be provided in the hub ring and the other in the outer joint member of a constant velocity joint.
The hub ring and the outer joint member may be fitted together and are crimped by being at least locally diametrically expanded or contracted, whereby they can be reliably joined together while preventing loosening.
Alternatively, the hub ring and the outer joint member may be fitted together and separably fastened. For example, they are axially tightened with a threaded end of a stein portion of the outer joint member. Thus, the hub ring and the outer joint member are detachable from the attaching member independently from each other, which allows only one that has been damaged to be repaired with great facility and economy.